
    <!DOCTYPE html>
    <html lang="zh-CN">
    <head>
      <meta charset="UTF-8">
      <meta name="viewport" content="width=device-width, initial-scale=1.0">
      <title>如何配置和优化网络参数以提高网络吞吐量和降低延迟？ - 交互式测验</title>
      <style>
        @import url('https://fonts.googleapis.com/css2?family=Noto+Sans+SC:wght@400;500;700&display=swap');
        
        body {
          font-family: 'Noto Sans SC', sans-serif;
          background-color: #f4f7f9;
          color: #333;
          display: flex;
          justify-content: center;
          align-items: center;
          min-height: 100vh;
          margin: 0;
          padding: 20px;
          box-sizing: border-box;
        }
        
        .main-wrapper {
            position: relative;
            width: 100%;
            max-width: 900px; /* Wider to accommodate buttons */
            display: flex;
            justify-content: center;
            align-items: center;
        }

        .quiz-container {
          background-color: #ffffff;
          border-radius: 16px;
          box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
          width: 100%;
          max-width: 700px;
          overflow: hidden;
          z-index: 10;
        }

        .quiz-header {
          background-color: #4a90e2;
          color: white;
          padding: 20px 30px;
          text-align: center;
        }

        .quiz-header h1 {
          margin: 0;
          font-size: 24px;
          font-weight: 700;
        }
        
        .quiz-header p {
            margin: 5px 0 0;
            font-size: 14px;
            opacity: 0.9;
        }

        .quiz-body {
          padding: 30px;
        }

        .progress-bar {
            display: none; /* 隐藏进度条 */
            width: 100%;
            background-color: #e0e0e0;
            border-radius: 5px;
            height: 10px;
            margin-bottom: 20px;
        }

        #progress-indicator {
            height: 100%;
            width: 0%;
            background-color: #4caf50;
            border-radius: 5px;
            transition: width 0.3s ease;
        }

        #question-container {
          margin-bottom: 20px;
        }

        #question-text {
          font-size: 18px;
          font-weight: 500;
          line-height: 1.6;
          margin-bottom: 25px;
        }

        .options-list {
          list-style: none;
          padding: 0;
          margin: 0;
        }

        .option-item {
          background-color: #f8f9fa;
          border: 1px solid #dee2e6;
          border-radius: 8px;
          padding: 15px;
          margin-bottom: 12px;
          cursor: pointer;
          transition: background-color 0.2s ease, border-color 0.2s ease;
        }

        .option-item:hover {
          background-color: #e9ecef;
        }
        
        .option-item.selected {
            background-color: #d1e7fd;
            border-color: #4a90e2;
        }

        .quiz-footer {
          padding: 20px 30px;
          display: flex;
          justify-content: space-between; /* 将按钮分布在两侧 */
          align-items: center;
          min-height: 65px; /* Reserve space */
        }

        .nav-btn {
          background-color: #4a90e2;
          color: white;
          border: none;
          border-radius: 8px;
          padding: 10px 20px;
          font-size: 16px;
          font-weight: 500;
          cursor: pointer;
          transition: background-color 0.2s ease, transform 0.2s ease;
          box-shadow: 0 4px 12px rgba(0,0,0,0.15);
        }
        
        #next-btn {
            background-color: #28a745;
        }

        .nav-btn:hover {
          background-color: #357abd;
          transform: scale(1.05);
        }
        
        .nav-btn:disabled {
            background-color: #a0c3e8;
            cursor: not-allowed;
            opacity: 0.7;
        }

        #result-container {
            border-top: 1px solid #eee;
        }
        
        .result-box {
            border-radius: 8px;
            padding: 20px;
            margin-top: 20px;
        }
        
        .result-box.correct {
            background-color: #d4edda;
            border: 1px solid #c3e6cb;
            color: #155724;
        }

        .result-box.incorrect {
            background-color: #f8d7da;
            border: 1px solid #f5c6cb;
            color: #721c24;
        }
        
        .result-box h3 {
            margin-top: 0;
        }

        .explanation-text {
            margin-top: 15px;
            line-height: 1.7;
        }
        
        .source-text {
            font-style: italic;
            font-size: 14px;
            margin-top: 15px;
            color: #555;
        }

        
        .final-score-container {
            padding: 40px;
            text-align: center;
        }
        .final-score-container h2 {
            margin-top: 0;
            margin-bottom: 30px;
        }
        .score-summary {
            display: flex;
            justify-content: center;
            gap: 20px;
            margin-bottom: 40px;
            flex-wrap: wrap;
        }
        .score-card {
            background-color: #f8f9fa;
            border-radius: 12px;
            padding: 20px;
            width: 180px;
            box-shadow: 0 4px 12px rgba(0,0,0,0.05);
            border: 1px solid #e9ecef;
        }
        .score-card h3 {
            margin: 0 0 10px;
            font-size: 16px;
            font-weight: 500;
            color: #555;
        }
        .score-card p {
            margin: 0;
            font-size: 28px;
            font-weight: 700;
            color: #333;
        }
        .score-details table {
            width: 100%;
            font-size: 16px;
        }
        .score-details td {
            padding: 4px 0;
        }
        .score-details td:last-child {
            text-align: right;
            font-weight: 700;
        }
        .report-actions button {
            background-color: #fff;
            border: 1px solid #ccc;
            border-radius: 8px;
            padding: 12px 25px;
            font-size: 16px;
            cursor: pointer;
            margin: 0 10px;
            transition: background-color 0.2s ease, border-color 0.2s ease, transform 0.2s ease;
        }
        .report-actions button:hover {
            background-color: #f1f1f1;
            border-color: #bbb;
            transform: translateY(-2px);
        }
        .report-actions button.primary {
            background-color: #28a745;
            color: white;
            border-color: #28a745;
        }
        .report-actions button.primary:hover {
            background-color: #218838;
        }
        
        .hint-container {
            background-color: #e0f7fa;
            border: 1px solid #b2ebf2;
            border-radius: 8px;
            padding: 15px;
            margin-top: 20px;
            color: #006064;
            font-size: 15px;
            line-height: 1.6;
            display: none; /* 默认隐藏 */
        }
      </style>
    </head>
    <body>
      <div class="main-wrapper">
          <div class="quiz-container">
            <div class="quiz-header">
              <h1>如何配置和优化网络参数以提高网络吞吐量和降低延迟？ - 交互式测验</h1>
              <p>检验你对文档内容的理解程度</p>
            </div>
            <div id="quiz-content">
                <div class="quiz-body">
                    <div class="progress-bar">
                        <div id="progress-indicator"></div>
                    </div>
                    <div id="question-container">
                      <p id="question-text"></p>
                      <ul class="options-list" id="options-list"></ul>
                    </div>
                    <div id="result-container"></div>
                    <div id="hint-container" class="hint-container"></div>
                </div>
                <div class="quiz-footer" id="quiz-footer">
                  <button id="prev-btn" class="nav-btn">上一题</button>
                  <button id="hint-btn" class="nav-btn" style="background-color: #ffc107; color: #333; box-shadow: 0 4px 12px rgba(255,193,7,0.3);">提示</button>
                  <button id="next-btn" class="nav-btn">下一题</button>
                </div>
            </div>
          </div>
      </div>

      <script>
        const quizData = [
  {
    "question": "在进行Linux网络调优时，为了提高大流量数据传输的吞吐量，应该优先调整哪一组核心参数来增大TCP的发送和接收缓冲区最大值？",
    "options": [
      "net.ipv4.tcp_keepalive_time 和 net.ipv4.tcp_keepalive_intvl",
      "net.ipv4.ip_local_port_range",
      "net.core.wmem_max 和 net.core.rmem_max",
      "net.ipv4.tcp_congestion_control"
    ],
    "correctAnswerIndex": 2,
    "explanation": "net.core.wmem_max 和 net.core.rmem_max 这两个参数直接定义了操作系统允许为单个套接字分配的发送和接收缓冲区的最大内存大小。对于需要处理大流量数据的应用，增大这些值可以防止因缓冲区过小而导致的数据包丢弃，从而显著提高网络吞吐量。",
    "source": "文档中「1. 调整 TCP 参数」下的「TCP 窗口大小」部分",
    "hint": "文档中提到，这组参数用于“设置发送和接收缓冲区的最大大小”，以“帮助提高大流量数据的吞吐量”。"
  },
  {
    "question": "当系统管理员希望采用更现代的TCP拥塞控制算法（如BBR）来优化网络传输效率时，应修改哪个内核参数？",
    "options": [
      "net.ipv4.tcp_wmem",
      "net.ipv4.tcp_congestion_control",
      "ethtool -K eth0 gso off",
      "net.ipv4.tcp_keepalive_probes"
    ],
    "correctAnswerIndex": 1,
    "explanation": "net.ipv4.tcp_congestion_control 参数用于指定Linux内核所使用的TCP拥塞控制算法。通过将此参数的值设置为 'bbr' 或 'cubic' 等，可以选择不同的算法来应对不同的网络环境，从而达到提高吞吐量和降低延迟的目的。",
    "source": "文档中「4. 优化网络堆栈」下的「启用快速重传和拥塞控制」部分",
    "hint": "寻找文档中那个可以直接指定 'bbr' 或 'cubic' 算法的参数。"
  },
  {
    "question": "文档中提到的 `ethtool` 命令主要用于什么目的？",
    "options": [
      "监控实时的网络连接状态和端口信息",
      "配置底层网络接口卡（NIC）的硬件相关参数",
      "调整内核中TCP/IP协议栈的全局行为",
      "进行网络数据包的捕获和深度分析"
    ],
    "correctAnswerIndex": 1,
    "explanation": "`ethtool` 是一个专门用于查询和配置网络接口卡（网卡）驱动和硬件设置的命令行工具。它可以用来调整如接收/发送环形缓冲区大小（rx/tx）、硬件校验和、分片卸载（GRO/GSO）等底层参数，这些参数直接影响网卡的性能。",
    "source": "文档中「3. 配置网络接口」下的「调整网络接口参数」部分",
    "hint": "这个工具的作用是“配置网卡的参数，如关闭延迟、启用大帧、调整流控设置等”。"
  },
  {
    "question": "为了防止高网络负载下单个CPU核心因处理网络中断而过载，文档推荐了哪种优化方法？",
    "options": [
      "增大 `net.core.rmem_default` 的值",
      "将 `net.ipv4.tcp_congestion_control` 设置为 `bbr`",
      "使用 `ethtool` 关闭网卡的 GRO 和 GSO 功能",
      "配置中断负载均衡，将中断请求分散到多个CPU核心处理"
    ],
    "correctAnswerIndex": 3,
    "explanation": "当网络流量很大时，网络接口卡会产生大量中断请求，如果这些请求都由同一个CPU核心处理，会导致该核心性能瓶颈。通过配置中断负载均衡（如修改 rps_cpus/xps_cpus），可以将这些中断处理任务分配给多个CPU核心，从而有效避免单一核心过载，提升整体处理能力。",
    "source": "文档中「3. 配置网络接口」下的「调整中断负载均衡」部分",
    "hint": "这种技术的核心思想是“均衡中断负载，避免单一 CPU 过载”。"
  },
  {
    "question": "一个高并发的服务器频繁建立对外连接，导致出现“端口耗尽”的错误。应调整哪个参数来扩大可用的本地端口范围？",
    "options": [
      "net.ipv4.tcp_rmem",
      "net.ipv4.ip_local_port_range",
      "net.core.wmem_max",
      "net.ipv4.tcp_keepalive_time"
    ],
    "correctAnswerIndex": 1,
    "explanation": "net.ipv4.ip_local_port_range 参数定义了系统在建立出站连接时可以使用的临时（或称动态）端口号范围。当应用需要频繁创建大量出站连接时（例如代理服务器或微服务网关），扩大这个范围可以提供更多的可用端口，从而避免因端口耗尽而无法建立新连接的问题。",
    "source": "文档中「4. 优化网络堆栈」下的「调整内核网络堆栈参数」部分",
    "hint": "哪个参数直接控制了“本地端口范围”以“增加可用端口的数量”？"
  },
  {
    "question": "调整 `net.ipv4.tcp_keepalive_time`、`tcp_keepalive_intvl` 和 `tcp_keepalive_probes` 这组参数的主要目的是什么？",
    "options": [
      "提高TCP连接的初始建立速度",
      "增大网络传输的吞吐量",
      "维持长时间空闲连接的稳定性，并及时清理“僵死”连接",
      "减少网络数据包的传输延迟"
    ],
    "correctAnswerIndex": 2,
    "explanation": "TCP Keepalive机制用于探测一个TCP连接是否仍然有效。这组参数共同控制了探测行为：`tcp_keepalive_time` 定义了连接在多长时间空闲后开始发送探测包，`tcp_keepalive_intvl` 是探测包之间的时间间隔，`tcp_keepalive_probes` 是在放弃连接前发送的探测包数量。调整它们有助于在不确定的网络环境中（如NAT、防火墙）维持长连接的稳定性。",
    "source": "文档中「1. 调整 TCP 参数」下的「TCP 保活设置」部分",
    "hint": "这组参数的功能是“帮助维持长时间连接的稳定性”。"
  },
  {
    "question": "当需要对网络问题进行底层诊断，比如分析数据包的具体内容和传输序列时，文档推荐使用下列哪组工具？",
    "options": [
      "sysctl",
      "ethtool",
      "netstat, ss, iftop, nload",
      "tcpdump, Wireshark"
    ],
    "correctAnswerIndex": 3,
    "explanation": "虽然 `netstat`、`ss` 等工具能提供连接状态和流量统计的宏观视图，但它们无法展示数据包的内部细节。`tcpdump` 和 `Wireshark` 是专业的网络协议分析工具，它们能够捕获网络接口上的原始数据包，并对其进行解码和详细分析，是诊断复杂网络问题的终极手段。",
    "source": "文档中「5. 监控和调试」下的「使用监控工具」部分",
    "hint": "文档中明确提到，用于“进行网络抓包和分析，诊断性能问题”的工具是？"
  }
];
        console.log("Quiz Data:", JSON.parse(JSON.stringify(quizData))); // 添加这行用于调试，以可展开的JSON格式输出
        
        let currentQuestionIndex = 0;
        let score = 0;
        // 存储每个问题的回答状态
        const userAnswers = new Array(quizData.length).fill(null); 

        const questionTextEl = document.getElementById('question-text');
        const optionsListEl = document.getElementById('options-list');
        const resultContainerEl = document.getElementById('result-container');
        const quizContentEl = document.getElementById('quiz-content');
        const progressIndicatorEl = document.getElementById('progress-indicator');
        const prevBtn = document.getElementById('prev-btn');
        const nextBtn = document.getElementById('next-btn');
        const hintBtn = document.getElementById('hint-btn');
        const hintContainerEl = document.getElementById('hint-container');

        function loadQuestion() {
          resultContainerEl.innerHTML = '';
          optionsListEl.innerHTML = '';
          hintContainerEl.style.display = 'none'; // 隐藏提示
          
          if (currentQuestionIndex >= quizData.length) {
            showFinalScore();
            return;
          }

          updateProgress();

          const currentQuestion = quizData[currentQuestionIndex];
          questionTextEl.textContent = `(${currentQuestionIndex + 1}/${quizData.length}) ${currentQuestion.question}`;
          
          currentQuestion.options.forEach((optionText, index) => {
            const li = document.createElement('li');
            li.className = 'option-item';
            li.textContent = optionText;
            li.dataset.index = index; // Store index in a data attribute
            // 如果这道题已经回答过，恢复状态
            if (userAnswers[currentQuestionIndex] !== null) {
                if (index === userAnswers[currentQuestionIndex]) {
                    li.classList.add('selected');
                }
            }
            optionsListEl.appendChild(li);
          });

          // 如果已经回答过，直接显示结果
          if (userAnswers[currentQuestionIndex] !== null) {
              const isCorrect = userAnswers[currentQuestionIndex] === currentQuestion.correctAnswerIndex;
              showResult(isCorrect, currentQuestion);
          }
          
          updateNavigationButtons();
          updateProgress();
        }

        function selectOption(optionIndex) {
            userAnswers[currentQuestionIndex] = optionIndex;
            const currentQuestion = quizData[currentQuestionIndex];
            const isCorrect = optionIndex === currentQuestion.correctAnswerIndex;

            // 重新计算分数
            score = userAnswers.reduce((acc, answer, index) => {
                return answer === quizData[index].correctAnswerIndex ? acc + 1 : acc;
            }, 0);

            showResult(isCorrect, currentQuestion);
            updateNavigationButtons();
        }
        
        function updateProgress() {
            const answeredQuestions = userAnswers.filter(answer => answer !== null).length;
            const progressPercentage = (answeredQuestions / quizData.length) * 100;
            progressIndicatorEl.style.width = `${progressPercentage}%`;
        }
        
        function updateNavigationButtons() {
            prevBtn.style.display = 'block';
            nextBtn.style.display = 'block';
            hintBtn.style.display = 'block'; // 显示提示按钮

            prevBtn.disabled = currentQuestionIndex === 0;
            nextBtn.disabled = false; // 最后一题时，下一题按钮不禁用，而是用于显示报告
            nextBtn.textContent = (currentQuestionIndex === quizData.length - 1) ? '查看报告' : '下一题';
            
            // 如果当前问题没有提示，则禁用提示按钮并隐藏提示内容
            if (!quizData[currentQuestionIndex].hint) {
                hintBtn.disabled = true;
                hintContainerEl.style.display = 'none';
                hintContainerEl.textContent = ''; // 清除旧的提示内容
            } else {
                hintBtn.disabled = false;
            }
        }

        function showResult(isCorrect, questionData) {
            resultContainerEl.innerHTML = ''; // 清空之前的结果
            const resultBox = document.createElement('div');
            resultBox.className = `result-box ${isCorrect ? 'correct' : 'incorrect'}`;
            
            let html = `<h3>${isCorrect ? '回答正确！' : '回答错误'}</h3>`;
            if (!isCorrect) {
                html += `<p><strong>正确答案是：</strong> ${questionData.options[questionData.correctAnswerIndex]}</p>`;
            }
            html += `<div class="explanation-text">${questionData.explanation}</div>`;
            html += `<div class="source-text">来源: ${questionData.source}</div>`;
            
            resultBox.innerHTML = html;
            resultContainerEl.appendChild(resultBox);

            // 禁用所有选项的点击事件，并高亮正确/错误答案
            Array.from(optionsListEl.children).forEach((child, index) => {
                child.style.pointerEvents = 'none';
                // 高亮正确答案
                if (index === questionData.correctAnswerIndex) {
                    child.classList.add('correct'); // 需要添加CSS样式
                    child.style.backgroundColor = '#d4edda';
                    child.style.borderColor = '#c3e6cb';
                }
                // 如果选错了，高亮错误选项
                if (!isCorrect && index === userAnswers[currentQuestionIndex]) {
                    child.classList.add('incorrect'); // 需要添加CSS样式
                    child.style.backgroundColor = '#f8d7da';
                    child.style.borderColor = '#f5c6cb';
                }
            });
        }

        function goToNextQuestion() {
            if (currentQuestionIndex < quizData.length - 1) {
                currentQuestionIndex++;
                loadQuestion();
            } else {
                showFinalScore();
            }
        }

        function goToPreviousQuestion() {
            if (currentQuestionIndex > 0) {
                currentQuestionIndex--;
                loadQuestion();
            }
        }
        
        function showHint() {
            const currentQuestion = quizData[currentQuestionIndex];
            if (currentQuestion.hint) {
                hintContainerEl.textContent = currentQuestion.hint;
                hintContainerEl.style.display = 'block';
            } else {
                hintContainerEl.style.display = 'none';
            }
        }

        function showFinalScore() {
            document.querySelector('.quiz-body').style.display = 'none';
            document.getElementById('quiz-footer').style.display = 'none';

            const correctCount = score;
            const totalQuestions = quizData.length;
            const answeredCount = userAnswers.filter(a => a !== null).length;
            const wrongCount = answeredCount - correctCount;
            const skippedCount = totalQuestions - answeredCount;
            const accuracy = totalQuestions > 0 ? Math.round((correctCount / totalQuestions) * 100) : 0;
            const errorRate = totalQuestions > 0 ? Math.round((wrongCount / totalQuestions) * 100) : 0;

            const finalScoreHtml =
                '<div class="final-score-container">' +
                '<h2>答题报告</h2>' +
                '<div class="score-summary">' +
                '<div class="score-card">' +
                '<h3>得分</h3>' +
                '<p>' + correctCount + ' / ' + totalQuestions + '</p>' +
                '</div>' +
                '<div class="score-card">' +
                '<h3>正确率</h3>' +
                '<p>' + accuracy + '%</p>' +
                '</div>' +
                '<div class="score-card">' +
                '<h3>错误率</h3>' +
                '<p>' + errorRate + '%</p>' +
                '</div>' +
                '<div class="score-card score-details">' +
                '<table>' +
                '<tr><td>正确</td><td>' + correctCount + '</td></tr>' +
                '<tr><td>错误</td><td>' + wrongCount + '</td></tr>' +
                '<tr><td>未答</td><td>' + skippedCount + '</td></tr>' +
                '</table>' +
                '</div>' +
                '</div>' +
                '<div class="report-actions">' +
                '<button id="review-btn">回顾测验</button>' +
                '<button class="primary" onclick="location.reload()">再试一次</button>' +
                '</div>' +
                '</div>';

            let reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }
            quizContentEl.insertAdjacentHTML('beforeend', finalScoreHtml);
            document.getElementById('review-btn').addEventListener('click', reviewQuiz);
        }

        function reviewQuiz() {
            const reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }

            document.querySelector('.quiz-body').style.display = 'block';
            document.getElementById('quiz-footer').style.display = 'flex';
            
            currentQuestionIndex = 0;
            loadQuestion();
            updateNavigationButtons(); // Ensure nav buttons are correctly displayed
        }

        // Event Delegation for options
        optionsListEl.addEventListener('click', (event) => {
            if (event.target && event.target.matches('li.option-item')) {
                // Check if the question has already been answered
                if (userAnswers[currentQuestionIndex] === null) {
                    const selectedIndex = parseInt(event.target.dataset.index, 10);
                    selectOption(selectedIndex);
                }
            }
        });

        prevBtn.addEventListener('click', goToPreviousQuestion);
        nextBtn.addEventListener('click', goToNextQuestion);
        hintBtn.addEventListener('click', showHint);
        
        // 初始加载
        loadQuestion();
      </script>
    </body>
    </html>
  